Question
Question: A real point object is kept at distance \(\frac { \mathrm { f } \text { ' } } { 2 }\) from a conve...
A real point object is kept at distance 2f ’ from a convex lens on principle axis as shown. Another concave lens of focal length '2f' is suppose to be kept on the other side of convex lens so that a final real image is formed. The distance 'x' of concave lens from convex lens must satisfy :
A
0 < x < f
B
f < x < 2f
C
0 < x < 2f
D
None of these
Answer
None of these
Explanation
Solution
Image formed by convex lens is at a distance 'f' from it.
u = –f/2
f = + f
from here we get
v = – f
Above image will behave as object which will be real for concave lens and it can't form real image.